The present invention relates to a nonwoven fabric having at least two layers of nonwoven web. More particularly, the present invention relates to a nonwoven fabric wherein one of the layers comprises a web having monofilaments or fibers made from polypropylene and another layer comprises a nonwoven web having monofilaments or fibers made from polyethylene.
Nonwoven materials are, of course, well known in the art. Such materials were developed primarily in the 1950's and 1960's, although at least one reference dates back to 1943 (see, e.g., U.S. Pat. No. 2,336,743 to Manning).
One of the most significant commercial applications of nonwoven fabrics is in the fabrication of disposable products intended for a single use. Typical of such products are disposable diapers, feminine care products, surgical gowns, industrial wipes, and the like. Because the nonwoven fabric is intended as a cloth substitute in these applications, extensive effort has been expended to improve the properties of nonwoven fabric to more nearly approximate that of cloth. Of particular interest has been the softness of the nonwoven web, that is, improving the feel or "hand" of the fabric together with lowering the resistance of the fabric to folding or bending. Another important area has been the improvement of the nonwoven web's tensile strength or tear resistance. Yet another area has been the development of nonwoven fabrics with specific wettability characteristics.